Serpentine belt trouble

Nad_Yvalhosert · Oct 20, 2020

Second: if you find no leaks, purchase a new drier. The desiccant is wasted after this much time.
Get a new orifice tube. Change ONLY the o-rings that you disturb
Add 2 oz of A/C oil into the drier. Reassemble and get to an A/C shop for a proper evac and vacuum service. Anything around 20 mins holding vacuum is decent, a half hour is better.
If it holds vacuum for 5 mins after the 20+ mins, charge.

This is important: Use 80% of the R12 quantity on the info sticker (it's either on the drier or the compressor)

Literature I've read says the old oil in the system is compatible with the new refrigerant, though if you want to go through the time of tearing apart the other parts to wash/flush and risk galling the aluminum threads, have at it

Nad_Yvalhosert · Oct 20, 2020

Or just take it to an A/C repair shop and ask them to do a retrofit.

Andrew7 · Oct 21, 2020

Nad_Yvalhosert said:
So you say you have an R12 A/C system, that means 88-91. '92 was a transition year.

After the belt problem is fixed
After the winter is over
Then you can address the A/C system

First. Install the retrofit fittings and add a pound of R134a with Dye Just enough to potentially get the compressor pumping. Let her run 20 mins or so, to get the dye spread throughout the system. Check for leaks, repair as necessary. If you replace any parts, add 2 oz of new oil, plus the same amount of any you drain out.
Example: if you change the compressor, drain the old oil into a measuring cup. Say you get 1 oz. You'll add 3 oz into the new compressor

It’s a ‘93 with big block but older Freon version.

Nad_Yvalhosert · Oct 21, 2020

Good. My info still applies.

After you fix the belt problem...

Steve A · Oct 27, 2020

I have to respectfully disagree on a couple points Nad_Yvalhosert makes. As you note your 93 has an R12 system, the EPA mandated year of the switch to R134a refrigerant was 1994. You must change your accumulator (sometimes referred to as drier) for the simple reason that you probably don't know definitively which dessicant is in it. It must contain either XH7 or XH9 dessicant (all the new ones do) to be compatible with R134a oils. If you change the accumulator, which is the lubricant reservoir, and drain the compressor you've eliminated most of the mineral oil the factory serviced R12 systems with. R134a will NOT pickup and circulate mineral oil, you must reservice with an oil that 134 will carry in order to lubricate the system components. I've done a few retrofits of R12 systems and have used ester oil, because it is compatible with R12 and R134a, with good results. Another thing I would do is replace every o-ring in the system with new HNBR seals (R134a compatibility), no sense taking a chance on an old seal in a virtually fresh system. Absolutely change the orifice tube, it's the only filter in the system. Lube all the new o-rings with mineral oil when reassembling connections. If you don't have the equipment to vacuum the system down and reservice it by all means go to a reputable shop to have it done, but doing most of the rest of the work has two benefits: a) you save a good chunk of change and b) you learn how the stuff works and you know HOW it was done.

Serpentine belt trouble

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